D. (21 Points) Let A, B and C be 3 sets. a. Find a counterexample to the statement A ( B C ) = ( A B ) C i. b. Without using Venn diagram, prove that A ( B C ) = ( A B ) ( A C ) i. c. Without using Venn diagram, prove that A \ ( B \ C ) = ( A \ B ) ( A \ C c ) i..